a. Field of the Invention
The present invention pertains to a doffing apparatus for a spinning frame, and more particularly, it relates to a doffing apparatus for a spinning frame such as a flyer-type roving machine carrying bobbins whose lower end portions are received shallowly in bobbin wheels and whose upper end portions are driven by spindles, said spinning frame being designed to be operative that the bobbins are first relieved of their engagement with said spindles and then they are lifted to some distance above said bobbin wheels to be completely detached from these bobbin wheels during the doffing operation.
B. Description of the Prior Art
As the means for mechanically carrying out doffing operation, there have been proposed doffing apparatuses in, for example, Japanese Patent Publication No. 40-18053 and Japanese Patent Publication No. 48-8298 Specifications. These known doffing apparatuses are invariably arranged to be operative so that, after the full bobbins are taken out of the spinning frame while being supported on appropriate bobbin-supporting means, these full bobbins are transferred onto a bobbin-conveying means disposed close to and alongside the spinning frame, and then empty bobbins which are brought to the side of the spinning frame by the same bobbin-conveying means are received by said bobbin-supporting means to be transferred onto the spinning frame. Thus, the full bobbins which have been removed from the spinning frame can be carried directly to a subsequent step by the bobbin-conveying means and empty bobbins also can be conveyed by the same bobbin-conveying means, whereby these apparatuses have been considered to effectively contribute to rationalization of not only the doffing operation but also the bobbin-conveying operation.
However, the aforesaid known apparatuses have the following problems in both the receiving and transferring of full and empty bobbins between the bobbin-supporting means and the bobbin-conveying means.
That is to say, in that part of operation wherein full bobbins from the spinning frame are transferred onto the bobbin-conveying means by the bobbin-supporting means, it is mandatory that no bobbins are present on the correspondingly positioned bobbin holders of the bobbin-conveying means when the bobbin-supporting means supporting the full bobbins arrive at said bobbin-conveying means. It is also necessary that, by the time the bobbin-supporting means starts to move back to the spinning frame, this supporting means must have already completed the receiving of empty bobbins from the bobbin-conveying means. Because of these requirements, the known apparatuses are of the arrangement that, on the bobbin-conveying means which arrives at the spinning frame, there are interposed unoccupied bobbin holders (meaning carrying no bobbins) between those bobbin holders loaded with the empty bobbins, and that, after full bobbins have been transferred onto these unoccupied bobbin holders by the bobbin-supporting means, said bobbin-conveying means is caused to advance for a distance corresponding to the pitch of one bobbin holder to position the empty bobbins carried on the bobbin-conveying means so as to face the bobbin-supporting means which has already completed the transfer of the full bobbins, and that thereafter these empty bobbins are received by the bobbin-supporting means to be transferred onto the spinning frame.
As such, according to this prior doffing system, there is the inconvenience that, during one doffing operation, the bobbin-conveying means also has to be moved for a predetermined distance in synchronism with the action of the bobbin-supporting means. Thus, the smoothness of the whole operation is hampered, and besides, the control of actions of the apparatus becomes complicated.
Moreover, in the bobbin-conveying means of the known apparatus, a bobbin holder carrying no bobbin requires to be present always for every other bobbin pitch among the row of bobbin holders loaded with bobbins. Therefore, bobbin holders have to be provided on the conveying means in a number twice as many as the number of both full and empty bobbins which are to be conveyed actually. Not only that, there is a further inconvenience that the bobbin-conveying means will become excessively large in size.